Enormous Berry-Curvature-Based Anomalous Hall Effect in Topological Insulator (Bi,Sb)<sub>2</sub>Te<sub>3</sub> on Ferrimagnetic Europium Iron Garnet beyond 400 K.
basic_science · Level V
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- Record sourced from PubMed, PMID 35099945.
- Also identified by DOI 10.1021/acsnano.1c08663.
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Abstract
To realize the quantum anomalous Hall effect (QAHE) at elevated temperatures, the approach of magnetic proximity effect (MPE) was adopted to break the time-reversal symmetry in the topological insulator (Bi<sub>0.3</sub>Sb<sub>0.7</sub>)<sub>2</sub>Te<sub>3</sub> (BST) based heterostructures with a ferrimagnetic insulator europium iron garnet (EuIG) of perpendicular magnetic anisotropy. Here we demonstrate large anomalous Hall resistance (<i>R</i><sub>AHE</sub>) exceeding 8 Ω (<i>ρ</i><sub>AHE</sub> of 3.2 μΩ·cm) at 300 K and sustaining to 400 K in 35 BST/EuIG samples, surpassing the past record of 0.28 Ω (<i>ρ</i><sub>AHE</sub> of 0.14 μΩ·cm) at 300 K. The large <i>R</i><sub>AHE</sub> is attributed to an atomically abrupt, Fe-rich interface between BST and EuIG. Importantly, the gate dependence of the AHE loops shows no sign change with varying chemical potential. This observation is supported by our first-principles calculations via applying a gradient Zeeman field plus a contact potential on BST. Our calculations further demonstrate that the AHE in this heterostructure is attributed to the intrinsic Berry curvature. Furthermore, for gate-biased 4 nm BST on EuIG, a pronounced topological Hall effect-like (THE-like) feature coexisting with AHE is observed at the negative top-gate voltage up to 15 K. Interface tuning with theoretical calculations has realized topologically distinct phenomena in tailored magnetic TI-based heterostructures.